The invention relates to a method of regulating a steam turbine comprising at least one resuperheater arranged between a high pressure section and a low pressure section, wherein there is carried out a reference value-actual value comparison of the rotational speed and an adjustment magnitude derived from the reference value-actual value difference is delivered to a regulation valve arrangement. Further subject matter of the invention pertains to an apparatus for the performance of such method.
Steam turbine regulation encompasses a rotational speed regulation generally in the form of a direct rotational speed regulation with an essentially simple closed regulation circuit or in the form of a rotational speed regulation or frequency-output regulation, for instance, as an output regulation circuit having a subordinated rotational speed regulation circuit. In both instances there is carried out a reference value-actual value comparison of the rotational speed and there is derived, directly or indirectly, an adjustment magnitude from the reference value-actual value difference. For the stability and quality of the regulation, i.e., for a rapid and oscillation-free transition between different, steady state operating conditions following the occurrence of surge-like disturbances, for instance, due to load surges at the power supply network of an electrical generator coupled with the turbine, there is required an optimization of the transition behavior of the regulation circuit, with appropriate damping. For this optimization there are available for complex regulation circuits different transmission elements having adjustable or selectable parameters, which, however, are associated with a comparatively high circuit expenditure. Particularly in the case of installations using mechanical or hydraulic, proportional-functioning rotational speed regulation, the attainment of a rapid and oscillation-free rotational speed-transition behavior can cause difficulties. Thi is especially true in the case of turbine-generator units which work both in the so-called island mode of operation and also in compound operation.